Checkout from src

src/Checkout.groovy

+class Checkout {
+    def run() {
+        println "Checkout module"
+        checkout scm
+    }
+}
\ No newline at end of file

vars/checkout.groovy

 #!/usr/bin/env groovy
 
 def call(body) {
-    checkout scm
+    new Checkout().run()
     return this
 }